cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A377300 G.f.: Sum_{k>=1} k * x^(k*(7*k - 7 + 2)/2) / (1 - x^k).

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%I A377300 #10 Oct 23 2024 08:47:53
%S A377300 1,1,1,1,1,1,1,1,3,1,3,1,3,1,3,1,3,1,3,1,3,1,3,4,3,1,6,1,3,4,3,1,6,1,
%T A377300 3,4,3,1,6,1,3,4,3,1,6,5,3,4,3,5,6,1,3,8,3,1,6,5,3,4,3,5,6,1,3,8,3,1,
%U A377300 6,5,3,4,3,5,11,1,3,8,3,6,6,5,3,4,8,5,6,1,3,13
%N A377300 G.f.: Sum_{k>=1} k * x^(k*(7*k - 7 + 2)/2) / (1 - x^k).
%C A377300 In general, for d > 0, if g.f. = Sum_{k>=1} k * x^(k*(d*k - d + 2)/2) / (1 - x^k), then Sum_{k=1..n} a(k) ~ 2^(3/2) * n^(3/2) / (3*sqrt(d)).
%H A377300 Vaclav Kotesovec, <a href="/A377300/b377300.txt">Table of n, a(n) for n = 1..10000</a>
%F A377300 Sum_{k=1..n} a(k) ~ 2^(3/2) * n^(3/2) / (3*sqrt(7)).
%t A377300 Table[Sum[If[n > 7*k*(k-1)/2 && IntegerQ[n/k - 7*(k-1)/2], k, 0], {k, Divisors[2*n]}], {n, 1, 100}]
%t A377300 nmax = 100; Rest[CoefficientList[Series[Sum[k*x^(k*(7*k - 7 + 2)/2)/(1 - x^k), {k, 1, Sqrt[2*nmax/7] + 1}], {x, 0, nmax}], x]]
%Y A377300 Column 7 of A334466.
%K A377300 nonn
%O A377300 1,9
%A A377300 _Vaclav Kotesovec_, Oct 23 2024